Cortisol Blood Test

A cortisol test is done to measure the level of the hormone cortisol in the blood. This test is effective at tracking the extremes of cortisol abnormality. The cortisol level may show problems with the adrenal glands or pituitary gland. If your cortisol levels are too high or too low, it may mean you have a disorder of your adrenal glands. These disorders can be serious if not treated.

Normal values for a blood sample taken at 8 in the morning are 5 to 25 mcg/dL or 140 to 690 nmol/L. Normal values depend on the time of day and the clinical context.

What is a low level of cortisol?

Low levels of cortisol can cause weakness, fatigue, and low blood pressure. You may have more symptoms if you have untreated Addison's disease or damaged adrenal glands due to severe stress, such as from a car accident or an infection. These symptoms include sudden dizziness, vomiting, and even loss of consciousness.

What is a high level of cortisol?

Too much cortisol can produce some of the hallmark signs of Cushing syndrome — a fatty hump between your shoulders, a rounded face, and pink or purple stretch marks on your skin. Cushing syndrome can also result in high blood pressure, bone loss and, on occasion, type 2 diabetes.